The present disclosure relates to a memory element storing information based on any change of electrical characteristics observed in a memory layer including an ion source layer and a resistance change layer, to a method of manufacturing the same, and to a memory device.
In information devices such as computers, a random access memory widely in use is a DRAM (Dynamic Random Access Memory), which operates at a high speed and is high in density. The DRAM is, however, high in manufacturing cost due to the complicated manufacturing process thereof compared with that of a logic circuit LSI (Large Scale Integrated circuit) or of a signal processing circuit generally used for electronic devices. The DRAM is also expected for a frequent refresh operation, i.e., an operation for reading any written information (data), and amplifying again the information for rewriting thereof as is a volatile memory from which any stored information is lost when power is turned off.
As a nonvolatile memory from which information is not erased even if the power is turned off, previously proposed are a flash memory, a FeRAM (Ferroelectric Random Access Memory), an MRAM (Magnetoresistive Random Access Memory), and others. Such types of memories are able to keep any written information for a long time with no supply of power. However, such types of memories each have advantages and disadvantages. Specifically, the flash memory is indeed high in packaging density, but is disadvantageous in terms of operation speed. The FeRAM has the limitations for microfabrication to achieve a higher packaging density, and also has a disadvantage in a manufacturing process. The MRAM has a disadvantage in terms of power consumption.
For overcoming such disadvantages, a next-generation nonvolatile memory currently proposed includes a ReRAM (Resistive Random Access Memory) or a PCM (Phase Change Memory) as a memory element of a new type (for examples, see Japanese Patent Application No. 2006-322188 and Japanese Unexamined Patent Application Publication No. 2009-43873.